‘Magic potions’ can’t cure gardening ills

Thursday

Apr 6, 2017 at 5:19 PMApr 6, 2017 at 5:22 PM

Al HightSpecial to the Topsail Advertiser

Thirty plus years of working in horticulture as taught me many things: Don’t prune your sister-in-law’s Japanese maple; run away as fast as you can when a potential client describes themselves as “easy to work with;” and be very careful when criticizing magic potions and botanical dogma that are held in high esteem by some gardeners. But, being a bit of an April fool (happy belated April Fool’s Day, everyone), I will make my way to the end of the branch and see how quickly I can saw it off behind me. It certainly won’t be the first time I fell out of a tree.

Gardeners love “magic potions” that promise more of everything: growth, flowers, fruit or an easy cure for a pest problem. There is usually some level of underlying truth to them. But, we need to dig deeper (sorry for the gardening pun).

How many times have you been told to put out “bloom-booster” fertilizer with lots of extra phosphorus (the middle number on the container) to have more flowers? It’s true that phosphorus is an essential nutrient is most of the processes that happen inside a plant including forming flowers. But, once you have met the amount needed, adding more isn’t going to make the flower show any better.

Soils that have been fertilized over the years usually have enough phosphorus to grow plants for a long time. But, if your garden was recently carved out of a wooded area that no farmer ever laid a plow to, you may need lots of phosphorus to grow anything. So, get the soil tested. Your local extension office has everything you need to get that done.

Another one that drives me to distraction is vitamin solutions for plants. Plants do use vitamins but they make their own. You won’t find any legitimate research showing a positive response to vitamin applications in plants.

Other products are believed to cure what ails everything on a certain plant. Southern magnolia not doing well? Swing by the supermarket and pick up some Epsom salts. Pecan tree looking a little funny? Bury a container of Red Devil lye and you’ll be as nutty as a fruitcake.

Epsom salts is magnesium sulfate. If you have sandy soils that are very high or very low pH, the magnesium may be the right solution. Otherwise, save the Epsom salts to soak your tired feet.

What about the lye? There is a problem called pecan rosette that’s caused by zinc deficiency. The ends of some of the branches are distorted. I’ve never seen a case of it in North Carolina, but that doesn’t mean it hasn’t happened. Lye is a source of zinc but, if you need zinc, there are much better ways to get it. Fertilizers with a “micronutrient package” are a good example.

Fighting diseases in our hot and humid climate is another gardening challenge. We have excellent fungicides but many people don’t like using them. So, they’re always looking for an alternative. Some of what you see recommended works and others don’t.

If you’re attempting to grow roses without pesticides in this climate, good luck. Controlling the common rose disease black spot is difficult even with the traditional fungicides, but you do have an alternative that actually works: milk. It’s much more expensive but it is fairly effective.

Vinegar is an alternative disease control you will see recommended that doesn’t work. The rates that might fight the fungus will injure the plant.

Speaking of injuring plants, you’ll also see vinegar recommended to control weeds. Killing weeds requires commercial strength vinegar with 70 to 80 percent acetic acid. The stuff you put on your turnip greens is about 10 percent at the most.

Our charge at N.C. State University Extension is to give you science and research-based information. That doesn’t mean we’re always right but we won’t hand out any potions in little brown bottles or recommend concoctions of household items.

Check out our website Check ces.ncsu.edu where you can submit questions via the ‘Ask an Expert’ link, or contact your local Cooperative Extension center by phone: If you live in Pender County, call 910-259-1238; in New Hanover County, call 910-798-7660; in Brunswick County call 910-253-2610. You can also find great local information at nhcarboretum.com and on Facebook. Just search for “New Hanover County Arboretum.”

Al Hight is the extension director for the North Carolina Cooperative Extension in New Hanover County. Contact him at 910-798-7666.